What's happening right now in Fukushima is terrible, for sure. But how does it rank in the pantheon of nuclear disasters? We humans have had an awful lot of atomic foulups; here are the ones that have caused the most widespread contamination and destruction.

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10. Castle Bravo, a Botched Hydrogen Bomb Test
In 1954, some engineers from Los Alamos National Laboratory made a little miscalculation before a nuclear weapons test. Their hydrogen bomb was more than twice as powerful as expected. It created a 15 megaton blast that showered a Japanese fishing boat and several Pacific islands with radioactive fallout.

9. Three Mile Island
In 1979, just weeks after a Jane Fonda movie (The China Syndrome) raised questions about the safety of nuclear power, a valve in the cooling system of the Three Mile Island nuclear reactor failed. It was stuck open, allowing lots of coolant water to escape. To make matters worse, an indicator light had gone out, which mislead the plant operators to think that the valve was closed. Over the course of several hours, the nuclear reactor overheated and had a partial meltdown. There was a small explosion, and a miniscule amount of radioactive material was released outside of the plant. The inside of the plant, however, was highly contaminated, and had to be shut own. The initial cleanup effort cost nearly a billion dollars.

8. Baneberry test
Of the many nuclear weapons tests conducted at Yucca Flat in Nevada, this 1970 explosion was the biggest disaster. Although the warhead was buried 900 feet below ground, it sent a plume of iodine-131-packed gas up into the jet stream. Soon after, radioactive snow was falling in Northern California.

7. Rocky Flats
At the Rocky Flats nuclear weapons plant in Colorado, scientists would handle huge chunks of plutonium that were kept inside of workstations called glove boxes. On at least two occasions, the radioactive material caught on fire. The worst of those incidents happened in 1969, when nearly five kilograms of plutonium went up in flames. A plume of radioactive smoke escaped from the laboratory, which was shut down several years later.

6. Fukushima
When a Tsunami stuck the Fukushima nuclear power plant in March of 2011, some of its cooling systems failed, sending several reactors spiraling out of control. As temperatures within the reactors rose, massive explosions shook the power plant, releasing some radioactive material and damaging the barriers that are meant to contain nuclear material. In a last ditch effort, nuclear power authorities flooded the reactors with seawater, ensuring that the plant will never again be used. Although this situation is not over yet, it appears to be far worse than the Three Mile Island incident.

5. Kyshtym disaster
There were problems at the Mayak nuclear reprocessing facility from the getgo. In 1957, the cooling system for a large nuclear waste tank at plant failed. There was a huge explosion. It blanketed an area of nearly a thousand square kilometers with radioactive material, mostly caesium-137 and strontium-90, which is really bad stuff. The International Atomic Energy Agency ranked it as the second worst nuclear power accident in the world.

4. Goiania incident
In 1987, a little girl sat on the floor of her home playing with a glowing blue powder. It was caesium - 137, a highly radioactive material. Her father, a junkyard owner, had bought the deadly substance from a pair of men who had broken into an abandoned medical building, looking for scrap metal to sell. The junkyard owner's wife, daughter, and two of his employees died after handling the substance. More than 245 other people fell ill after coming into contact with the radioactive isotope.

3. Hanford Nuclear Site
Over the course of several decades, the morons at Hanford Nuclear Site in Washington state accumulated massive amounts of radioactive waste and released some of it into the Columbia river. It is the most contaminated nuclear facility in the United States, and clean up efforts are costing more than $2 billion per year. By some estimates the total cleanup bill will reach $120 billion dollars.

2. Chernobyl
The most famous name in nuclear power plant disasters is near the top of the list for a reason: The nearby city of Pripyat is still contaminated. Late on the night of April 26th, 1986, a pair of engineers at the Chernobyl nuclear power plant started running a torture test, to find out what would happen if the reactor lost most of its power supply. It went horribly wrong, and became the worst nuclear accident in human history. Before the test, the engineers pulled too many control rods out of the reactor core. Those graphite poles act like brakes, slowing nuclear reactions. With the rods out, and power to the reactor steadily decreasing, the plant was poised for a catastrophe. Steam built up in the cooling system and there was a power spike, followed by an explosion. Someone pushed an emergency shutdown button, which automatically sent the control rods back into the reactor core. That was a mistake. It caused the reactor to overheat further. Eventually, the control rods caught fire, sending a shower of radioactive smoke over a wide swath of Europe and turning the nearby city of Pripyat, Ukraine into a nuclear wasteland. Within the plant, radiation levels climbed so high that some of the workers got a fatal dose within minutes. By some estimates, the disaster cost four thousand lives.

1. Hiroshima and Nagasaki
Unlike the many nuclear accidents that have occurred over the past century, America's decision to flatten Hiroshima and Nagasaki in 1945 killed upwards of a hundred thousand people, ended a war, and ignited an arms race that has slowed but not ended.